### Many objects that we come across in our daily life, are related to circular shape in some form or other like cycle wheels, round cake, papad, bangles, flower beds, etc. In this chapter, we shall review the concepts of perimeter (or circumference) and area of a circle and apply this knowledge in finding the areas of two special parts of a circular region known as sector and segment.

1.In the given figure, AB and CD are two diameters of a circle (with centre O) perpendicular to each other D and OD is the diameter of the smaller circle. If OA = 7 cm, then find the area of the shaded region.

#### CBSE 2013, 12,11

2. Find the area of the shaded region in the given figure, if  PR = 12 cm, PQ = 5 cm and
O is the centre of the circle.

#### CBSE 2009, 08

3. Find the area of shaded region in the figure below if  AC=16 cm, BC = 12 cm and O is centre of the circle. [take pie = 3.14]

#### CBSE 2011

4. A tool is prepared out of a circular metallic disc of  radius 14 cm, by taking out two semicircular parts of radius 7 cm each from the two sides as shown in the figure. Find the  area of the metal used in making 50 such tools

#### CBSE 2015

5. A wire when bent in the form of a square  enclosed an area 121 sq cm. If the wire was
bent in the form of a circle, then find the   area enclosed by the circle.

#### CBSE 2011

6. A road which is 7 m wide surrounds a  circular park whose circumference is  352 m. Find the area of road.

#### CBSE 2012

7.A 21 m wide athletic  track consists of two    straight sections 150 m long joining  semi-circular ends whose diameters are  84 m each (see the figure). Find the area of the track.